Spkotg-ptjlley for



MTE sTnTns PATENT OFFICE.

JOHN SHOPLAND, OF HONESDALE, PENNSYLVANIA.

SPRING-PULLEY FOR WINDOW-SASHES.

Specification of Letters Patent No.

To all whom 'it may concern.'

Be it known that I, JOHN SHOPLAND, of I-Ionesdale, in the county ofWayne and State of Pennsylvania, have invented certain new and usefulImprovements in Spring-Pulleys for I-Ianging Sash, Doors, &c.; and I dohereby declare the following to be a full, clear, and exact descriptionof the same, reference being had to the accompanying drawings, making apart thereof, in which- Figure l represents one of the pulleys inquestion as attached to a window frame, for operating the sash thereof.Fig. 2 represents a perspective view of the pulley stretched from theframe, and Fig. 3 represents a vertical cross section of the pulley,taken near its center.

Similar letters where they occur in the several figures denote likeparts in all.

The nature of my invention consists in providing a spring pulley, with aself acting spring brake, which shall compensate for the unequalstrength of the coiled spring in the pulley, as it is wound up, or letout, and thus causing it to act with more uniform power.

To enable others skilled in the art to make and use my invention, I willproceed to describe the same with reference to the drawings.

t, represents the frame in which the pulley B, is hung and wo-rks.l Thisframe has cast or wrought upon it two arms a, a', and a pivot b, uponwhich pivot, a drum c may be made for the spring to wind upon. Thepulley B, is made like a short cylinder, with one open end. Itsperiphery is provided with the customary groove or depression for thecord, or chain to wind upon. A coiled spring e, is arranged within thepulley wheel B, oneend of which coiled spring is attached to the pulley,and the other end to the pivot Z), or drum 0 upon it.

On the face of the closed end of the pulley wheel B, is cut a cam groovef, of a helical form, in which a small stud i, in the bar d, takes. Thebar d, passes through suitable 15,528, dated August 12, 1856.

openings in the arms a, @Q -its lower end resting upon a spring a,fastened on the underside of the lower arm (a). When the pulley wheel isturned so as to wind up its inclosed spring, the stud z', and the bar d,are carried by the helical groove f, toward the spring n-the end of saidbar pressing against said springwso that one spring shall counteract, orcompensate for the increasing power of the other one, as it continues tobe wound up.

In Fig. l, the spring pulley is shown as applied to a sash-h being thecord, chain, or band by which the sash is connected to said pulley. Inthis ligure the sash is represented as partially pulled down from thetop,-now continue to draw the sash down and the helical spring is woundup; but as it winds up, the stud z', in the bar ol, is held wit-h anincreasing pressure against the top of the groove f, by the increasingresistance of the spring n. So that to let go the sash at any point inits movement, it will remain there. Such couldnot be the case were itnot for the brake composed of the stud, bar, and a spring n, for it thehelical spring alone were used it would be either too weak when uncoiledto hold up the sash or too powerful when wound up to allow the sash. toremain down.

A spring and nut m, Fig. 2, may be used on the bar el, to regulate itspressure on the spring n, if found desirable.

Having thus fully described the nature of my invention what I claimtherein as new and desire to secure by Letters Patent is- In combinationwith the pulley and spring, the self acting compensating brake forholding the pulley at any fixed point, regardless of the increased powerof the coiled spring as it is wound up, in drawing down, or raising up asash, door, or other thing to which it may be attached, substantially asherein described.

JOHN SHOPLAND.

Witnesses:

A. B. STOUGHTON, THos. I-I. UPPERMAN.

